Looks like I have about 42 sets of headphones/earphones at the moment (yikes!), 9 of which are in current rotation. My faves right now are the Monster Turbine Pro Copper, Phiaton MS 400, AIAIAI TMA-1, Sennheiser IE8, and Audio Technica ATH-M50.

EDIT: Make that 43 total, and 10 in rotation...My Monster Miles Davis Tributes just arrived.